Electrically driven displacing mechanism



March 12, 1968 K. BRATSCHI 3,372,599 I ELECTRIQALLY DRIVEN DISPLACING MECHANISM Filed Jan. 10, 1966 INVENTOR, KONRAD BRATSCHI United States Patent 3,372,599 ELECTRICALLY DRIVEN DISPLACING MECHANISM Konrad Bratschi, Talgutweg 2, Ittigen, near Bern,

' Switzerland Filed Jan. 10, 1966, Ser. No. 519,547 Claims priority, application Switzerland, Jan. 13, 1965,

' 424/65 8 Claims. (Cl. 7489.2)

ABSTRACT OF THE DISCLOSURE An electrically driven displacing mechanism, for example for curtains, accordian-folded partitions, drawers, or display of advertising aids, which are guided along at least one rail by means of carrying elements, which mechanism comprises an endless conveying band or web in two sections extending along the rail, and entraining elements guided on the rail for conveying action back and forth, as well as two electrical terminal switches in the circuit of the electrical drive, which are actuated automatically corresponding to the two predetermined final conveying positions.

In mechanisms of this kind which have been used for curtains, resilient stops determining the final positions of a curtain are arranged on the rail for example, which open the associated terminal switch in the driving circuit on being struck by the sliders of the curtain. Whereas the one of these stops and terminal switches are situated at the end of therail adjacent to the driving motor, in order to keep the curtain in the open position reached, for example, the other stop and terminal switch must perforce be situated in the middle region of the rail length in .a two-piece contradirectional curtain system, or at the opposite end of the rail in a one-piece curtain system, in order to stop the curtain in the closed position.

Electrical connection conduits run along the rail, which is usually of metal, to this second terminal switch, this being the reason for strict requirements regarding the fitting of the leads, owing to the risk of short-circuiting.

Depending on local conditions, this results in considerable expense, and may detract from the'pleasant appearance of the mechanism. In addition, the electrical drive is switched off when the curtain reaches the opened position, by virtue of the fact that a column of curtain sliders pushed together by the one driving or entraining element strikes the 'stop, which may cause jamming of the sliders in the rail guide channel.

In another known switch-off system for electrically displaceable curtains, the tractive section is placed under tension when the curtain sliders strike a terminal stop, and the rapidly risingtension in the tractive section displaces a switching'cam transversely displaceable thereto, into the position interrupting the driving circuit. The participatingparts of the displacing mechanism are exces'sively stressed however, and the conveying web or cord, generally made of nylon or hemp, lengthens owing to this stress, in such degree that the switch-off action soon ceases to operate unless the length of the cord is reduced by the appropriate amount.

Another switch-off system for curtains has two terminal switches at the same extremity of the rail, of which one is arranged to be actuated by the pushed-together slider column of the fully gathered curtain, and the other by the last slider of the opened curtain. This requires precise initial calculation of the position of the curtain sliders when pulled apart, which is generally determined in practice by rigorous testing, the desirable precision not being retained in use however.

It is a main object of the present invention to eliminate tlliae shortcomings of the known arrangements specified a ove.

According to the invention an electrically actuated displacing mechanism for objects which are guided on a rail by means of carrying elements, comprises an endless driven conveying means having two sections extending along the rail, an electrical drive for said conveying means, entraining elements guided on the rail so as to be conveyed backwards and forwards along the rail, two electrical terminal switches in the circuit supplying the electrical drive which switches are arranged to be actuated automatically at two predetermined final conveying positions of the conveying means, a cursor fastened in longitudinally adjustable manner on each of the two sections of the conveying means, which cursors are independent of the entraining elements and are respectively arranged to actuate the terminal switches associated with the sections of the conveying means.

In order that the invention may be more clearly understood some embodiments thereof for use as a displacing mechanism for curtains, Will now be described, by way of example, with reference to the accompanying drawings in which:

FIGURES 1 to 3 each show a cross-section through the curtain rail according to the invention along the lines II, II-II and IIIIII in FIG. 4 as well as parts of the mechanism housed in the rail,

FIGURE 4 is a longitudinal section through the curtain rail with parts of the mechanism shown in side elevation,

FIGURE 5 shows a section of another curtain rail according to the invention fora two-piece set of curtains, and

FIGURES 6 and 7 schematically show the essential parts of the mechanism for an opened and closed twopiece contradirectional curtain system.

Referring to the drawings, a hollow section curtain rail 1 illustrated in FIGS. 1 to 4 has two channels 2 for reception of two longitudinal sections 3' and 3" of a driven conveying web, whose ends (not shown) are fastened to each other, and which runs over return pulleys or'the like at the two ends of the rail, and which may be driven in either direction of revolution by means of an electric motor 5, driving at least one point 4 of the pulley at one of the deflection points for the web (FIGS. 6 and 7).

Between the two channels 2 of the rail 1 is situated the guide channel 6 for the curtain sliders which are not shown. The guide channel 6 is connected at each side by a longitudinal slot 7 with the channels 2 and is open at the bottom, forming the outer longitudinal slot 8 of th rail.

Sleeve-shaped cursors 9 and 9" are respectively mounted on the two web sections 3' and 3" and are releasably fastened. by means of set screws 10 whose heads 11 are directed towards the channel 6 within the longitudinal slot 7 and are accessible from the outside at any time through the outer longitudinal slot 8, for example by means of an angled or ofiset screwdriver, so that the cursors may be displaced and refastened on the web or cord even after hanging the curtains.

At the end of the rail 1 adjacent to the motor 5 two conventional electrical end of travel switches 12' and 12" are mounted on the underside of the rail and on either side of the outer longitudinal slot 8, by means of an angle bracket 13 in each instance. The switches 12 and 12" interrupt the circuit of the driving motor 5 for one direction of revolution or the other, only by depression of their spring arm 14, and roller 15. The therminal switches 12' and 12" are respectively actuated by switching canis 16' and 16" longitudinally guided in the rail 1, supported like a slider in the slider channel 6 and projecting through the one connecting slot 7 or the other into the one or the other of the channels 2 and thus into the path of travel of one of the cursors 9' or 9" displaceable therein with the driving web so that the two switching cams do not touch and foul each other of the symmetrical halves of the cross-section of the slider channel 6. Projections 17 and 17" extend from the cams 16' and 16" through the outer longitudinal rail slot 8 below the rail, so that depression of the switch roller 15 opens the corresponding terminal switch 12' or 12" when the cam 16 or 16 is displaced by the cursor 9 or 9" in the one direction of revolution of the web or the other.

The outer end face of the switching cam 16' is thereby made to bear on a relatively weak return spring 18 which is supported 'on the casing 19 at the end of the rail adjacent to the motor and stores sufiicient energy as a result of the transmission from the motor 5 through the web, the cursor and cam, in order to impel the cam away from the roller 15 for the other direction of revolution of the web or cord. One return spring 18 only is required, for both cams 16- and 16", since only one of the cams is moved towards the spring in each case.

In the driving motor 5, which has two windings 31' and 32' respectively connected in series with the terminal switches 12' and 12", the change in direction of rotation is based on phase displacement by interposition of a condenser 32 as shown in the motor circuit 30. The terminal switch 12 supplies in closed position the winding 31, while the other terminal switch is in open position, and vice versa. The motor circuit 30 includes a reversing actuation switch 33, by means of which current may be fed to one terminal switch or the other in only one operating position in each case, and the current may be interrupted in a third position. This reversing switch 33 may be actuated manually, mechanically or else electrically, e.g. by a dimming switch employing a photoelectric cell.

When the revolution of the driven cord or web, e.g., clockwise as in FIG. 6 (showing the opening of a twopiece contradi-rectional curtain system 26', 26" by means of cntraining elements 27 and 27" connected to the corresponding web section) is terminated by the current interruption caused by the switching cam projection 17' acting on the terminal switch 12', the cord 'section 3' holds the switching cam 16' in the switched-off position reached, by means of the cursor 9, so that the terminal switch 12' remains open. Conversely, the terminal switch 12" has been returned to the closed position at the start of this cord displacement in the motor circuit which is then de-energised, as soon as the return spring 18 has pushed the cam 16" away from the roller 15 of the terminal switch 12". If the reversing switch is thereupon switched over into the other operating position for cord revolution anti-clockwise (closing movement of the curtains 26", 26"), the driven web (FIG. 7) revolves accordingly and allows the return spring 18 to push the cam 16 away from the roller 15 of the terminal switch 12, so that the switch 12 closes.

The conveying web with its two sections 3' and 3" and the cursors 9' and 9-", as well as the two switching cams 16' and 16", may also be employed in the curtain rail 20 shown in FIG. 5, wherein the channels 21 for the web sections extend side by side and are of equal size and spacing as in the rail 1, but wherein two slider channels 22 are each formed in the outer side of the rail adjacent to one or the other cord channel 21. A return spring 18 in FIG. 3 is accordingly situated in each slider channel 22.

In the case of great curtain spanning widths, or of several curtains or accordion-folded partitions displaceable by means of a single conveying cord, two synchronously operated driving motors may be used, one at each end of the rail. The electrical connection cable 23 can then advantageously be installed in the upper hollow space 24. or 25 of the rail 1 or 20,, wherein it is screened from sight, contact and damage by virtue of the rail mounting.

In the displacing mechanism described, the driving motor 5 need not be situated in the immediate vicinity of the end of the curtain, but may for example, be fastened in a wall recess or even in an adjoining room, if the end of the rail extends that far. This also applies in respect of displacing mechanism for other objects, for which a hidden arrangement of the drive is desirable.

What I claim is:

1. An electrically actuated displacing mechanism for objects which are guided on a rail by means of carrying elements, comprising an endless driven conveying means having two sections extending along the rail, an electrical drive for said conveying means, entraining elements guided on the rail so as to be conveyed backwards and forwards along the rail, two electrical terminal switches in the circuit supplying the electrical drive which switches are arranged to be actuated automatically at two predetermined final conveying positions of the conveying means, a cursor fastened in longitudinally adjustable manner on each of the two sections of the conveying means, which cursors are independent of the entraining elements and are respectively arranged to actuate the terminal switches associated with the sections of the conveying means.

2. A mechanism according to claim 1, wherein the conveying means is a web, each of the cursors is displaceably guided on the rail, two switching cams are respectively associated with the two sections of the web and are displaceably guided on the rail independently of the web, the switching cams are respectively arranged to open and close the terminal switches, and the cursors and the switching cams project into the path of travel of said objects from opposite sides of the rail.

3. A mechanism according to claim 2, comprising a return spring which is compressed by one of the switching cams when that cam switches off its terminal switch and is located between that switching cam and the end of the rail carrying the terminal switches.

4. A mechanism according to claim 3, wherein the rail is a hollow section rail having two channels for the two sections of the conveying web and at least one guiding channel for the carrying elements, the cursors are guided in the conveying web channels, and the switching cams are constructed as sliders supported in the carrying element channel and project into the conveying web channels as well as out of the rail through a longitudinal rail slot formed on the carrying element channel.

5. A mechanism according to claim 4, wherein the conveying web channels are connected to the carrying element channel through slots formed in the longitudinal sides of the carrying element channel, the cursors are fastened on the conveying web by means of screws whose heads are directed towards the carrying element channel and are accessible from the outside of the rail through the longitudinal rail slot.

6. A mechanism according to claim 5, wherein each switching cam occupies less than one symmetrical half of the channel cross-section in the carrying element channel.

7. A mechanism according to claim 3, characterised in that the return spring is housed in the carrying element channel in which is situated the switching cam which engages the return spring.

8. A mechanism according to claim 1, wherein at the side of the rail by which the rail is fastened, a channel is formed for reception of an electrical supply cable 6 References Cited UNITED STATES PATENTS 3,003,552 10/1961 Eilenberg 160345X 3,153,94 10/1964 Staak 160331X FOREIGN PATENTS 391,986 5/1965 Switzerland. 1,166,968 11/1958 France.

leading to the electrical drive, so that the cable is hidden, 10 FRED M ATTERN, JR Primary Examiner.

and is protected from contact and damage when the rail is fastened in position.

W. S. RATLIFF, Assistant Examiner. 

